The Subway Stray Current Monitoring Device Design Based On ARM-7 Chip

The transit of the subway rail is widely used in the way of DC power supply,and tracks can be used as the channel of the power supply circuit.While in the process of laying the track a variety of insulation measures have been implemented,these measures still can not do totally insulation.Leakage to earth and the surrounding soil from the track circuit current is referred to as stray current.Leaked this stray current will produce chemical corrosion of the concrete steel structure,the track,the track bed and the metal pipes of the rail transportation.With the passage of time,the strength and resistance of the structural steel corrosion has become less,serious threat to the operational safety and the equipment life.In order to avoid catastrophic accidents,to establish an effective stray current monitoring and the protective equipment has drawn increasing attention in the industry,and also it has important practical significance.With the rapid development of the microprocessor in recent years,embedded technology is more widely used in many industrial control field.Through in-depth analysis of the metro stray current monitoring methods and system requirements,this issue implement software and hardware design of the monitoring system.To NXP ARM7 architecture chip LPC2478 as the core,a variety of the peripheral circuit design a complete circuit diagram,combined with a variety of communication bus interface circuit,the SDRAM circuit,the Nandflash circuit,the LCD circuit of the resistance screen.Finally,the PCB design of the circuit have completed.On the basis of hardware,based on the open source u C/OS-? real-time operating system the system functions of friendly interactive and the automatic monitoring of stray current mainly include a variety of modules such as the communication module,the data storage module,the query module,the system management and the control of drain current cabinet and so on.The completion of these modules relate to a wide range of coordination among the kernel scheduling,the system migration,the underlying drivers,the communication protocols,the GUI functional design and other aspects.Finally,the system features carried out the actual measurement and the simulation test,and tests show that the system functions to meet the design requirements.So there are good practical value.